Solving Word Problems with Mixed Units of Length
Solving Word Problems with Mixed Units of Length is a Grade 4 math skill that applies addition and subtraction to measurements expressed in both feet and inches, or meters and centimeters. Students must add or subtract like units (feet with feet, inches with inches), then convert when the smaller unit total exceeds the conversion threshold (12 inches = 1 foot). For example, 3 ft 9 in + 2 ft 8 in = 5 ft 17 in = 6 ft 5 in after regrouping. Covered in Chapter 35 of Eureka Math Grade 4, this skill contextualizes measurement conversions in realistic scenarios.
Key Concepts
To solve a word problem involving mixed units of length, first determine the operation (addition or subtraction) needed to answer the question. Then, perform the calculation using one of the learned strategies, such as operating on like units or converting to the smallest unit.
Common Questions
How do I add feet and inches together?
Add feet to feet and inches to inches separately. If the total inches is 12 or more, convert groups of 12 inches to feet and add to the feet total. For example, 3 ft 9 in + 2 ft 8 in = 5 ft 17 in = 6 ft 5 in (since 17 = 12 + 5).
How many inches are in a foot?
There are 12 inches in 1 foot. This is the essential conversion for solving mixed length measurement problems. When inches reach 12, regroup into feet and remaining inches.
How do I subtract 4 ft 3 in from 6 ft 7 in?
Subtract like units: 7 in minus 3 in = 4 in; 6 ft minus 4 ft = 2 ft. Answer: 2 ft 4 in. If inches in the minuend were smaller than those in the subtrahend, you would first regroup 1 foot into 12 inches.
What if I need to regroup inches in a subtraction problem?
If the inches in the top number are smaller than the inches being subtracted, borrow 1 foot from the feet column and add 12 inches to the inches column. Then subtract normally. For example, 5 ft 3 in minus 2 ft 8 in: regroup to 4 ft 15 in, then subtract 2 ft 8 in = 2 ft 7 in.
What mixed length units do Grade 4 students work with?
Grade 4 students typically work with feet and inches in U.S. customary units, and meters and centimeters in metric units. Both systems require applying the like-units addition principle and knowing the conversion relationship (12 inches per foot, 100 centimeters per meter).
What chapter covers mixed length unit word problems in Eureka Math Grade 4?
Chapter 35: Problem Solving with Measurement in Eureka Math Grade 4 covers word problems involving mixed units of length, weight, and capacity using addition and subtraction with regrouping.